1. Field of the Invention
The present invention relates to a wiper intended to be used for wiping the human body, furniture, home fixtures and so on in a pre-moistened or dry state and a method for manufacturing the same.
2. Description of the Related Art
Nonwoven wipers have been widely used to wipe the human body, furniture, home fixtures and so on. Such wipers may be used in a dry state to absorb water during use or in a pre-moistened state. In either case, nonwoven wipers are formed of hydrophilic fibers such as rayon and synthetic resin fibers.
Japanese Patent No. 3183818 discloses a wet tissue in which an interlining layer is disposed between upper and lower layers. The upper and lower layers contain hydrophobic fibers at a higher proportion than hydrophilic fibers whereas the interlining layer contains hydrophilic fibers at a higher proportion than hydrophobic fibers. Fibers constituting these layers are entangled, fusion-bonded or entangled and fusion-bonded to impart a sufficient strength to a nonwoven fabric. In this wet tissue, the hydrophilic fibers function to retain water. With the hydrophobic fibers appearing on the tissue surfaces, moreover, the wet tissue is allowed to easily separate from another wet tissue.
Japanese Patent No. 3333718 discloses a wiper stack in which each wiper comprises two fibrous web layers of hydrophilic fibers, polyester fibers and heat-fusible fibers (or thermally bondable fibers) and a pulp fiber layer interposed therebetween. These layers are entangled and integrated together by high-pressure water streams, and the heat-fusible fibers are fusion-bonded to each other. Because the pulp fiber layer is provided as an interlining layer, this wiper is capable of retain much water and doesn't feel sticky to the touch.
In these wipers disclosed in Japanese Patent Nos. 3183818 & 3333718, the heat-fusible fibers are fusion-bonded to each other in the upper and lower surfacing layers between which the interlining layer is interposed to retain water. Thus, the fusion-bonded fibers appear on the sheet surface and make the sheet surface hard due to immovability. Accordingly, the wipers tend to irritate the skin when used for wiping the human body.
Unlike the Japanese Patent Nos. 3183818 & 3333718, there may be developed a wet tissue not containing heat-fusible fibers. However, just entangling hydrophilic fibers and synthetic resin fibers will result in decreased sheet strength, particularly decreased wet strength, so that when the wet tissue is used for wiping, it is likely that fibers fall out of the sheet surface or the sheet itself is broken.